1331312531 has 2 divisors, whose sum is σ = 1331312532. Its totient is φ = 1331312530.

The previous prime is 1331312513. The next prime is 1331312557. The reversal of 1331312531 is 1352131331.

Together with previous prime (1331312513) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1331312531 is a prime.

It is a super-2 number, since 2×1331312531² = 3544786110395251922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1331312497 and 1331312506.

It is not a weakly prime, because it can be changed into another prime (1331312581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665656265 + 665656266.

It is an arithmetic number, because the mean of its divisors is an integer number (665656266).

Almost surely, 2^1331312531 is an apocalyptic number.

1331312531 is a deficient number, since it is larger than the sum of its proper divisors (1).

1331312531 is an equidigital number, since it uses as much as digits as its factorization.

1331312531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 810, while the sum is 23.

The square root of 1331312531 is about 36487.1556989580. The cubic root of 1331312531 is about 1100.0860899563.

Adding to 1331312531 its reverse (1352131331), we get a palindrome (2683443862).

The spelling of 1331312531 in words is "one billion, three hundred thirty-one million, three hundred twelve thousand, five hundred thirty-one".